Acolytes (The Enclaves Book 1)

For Gaia, Tomma and Rosie, their cheerful childhood in the Female Enclave has hidden darker truths. Inducted at puberty into the Acolytes, they gradually discover the rigid restrictions and brutality that control the lives of every woman in the Encalve. The rigid controls and the Goddess fertility religion were introduced when the Enclave was founded, over one hundred years earlier, in response to the horrific pandemic that nearly wiped out the human population. And now those restrictions force Gaia to choose between her self and her loyalty to her sister-friends. For Tomma, it's about family, partners and children, all of which are prescribed by the Enclave, and none of them are what  she wants. And for traumatised Rosie, the fertility religion's restrictions push her to breaking – the rules, her sanity, and the barriers to her life's research. Each of the three girls is searching for her own true path, and their friendship will be tested beyond its limits. Will the Enclave survive what they must do? 

Acolytes (108000 words) is Book 1 of the Enclaves series by Nel Franks.